Chromium Oxide is a refractory colorant that is used to add a green color to slips, clay bodies, and glazes. This material easily produces a green color at all furnace conditions, making it a fast colorant. In glazes, up to 1% will give you muted greens and up to 3% will give you opaque and greyish greens. In slips and clay bodies, up to 5% will give you a variety of grey-greens.
Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.
